Historically, at the Ivies at this point in the process (Junior year Winter or earlier), the kids are asked for their academics (test scores and grades) and their chance of admission is assessed by the coaching staff, who are likely to be biased towards giving the thumbs up for someone they want. The admissions departments don't get involved until Summer at the earliest and the Likely Letters go out in the Fall (the real admission assessment). The coaches are making admissions assessments and commitments based on experience in absence of formal admissions review.
IMHO, that is deceptive. While coaches at any school will usually tell recruits that admission is dependent on continued academic performance, the assumption is that if a coach tells you you can get in that you can if you continue to perform at the same level. At schools like BU, BC, UM, etc. the admissions team will review academics earlier than the Ivies and make actual admissions commitments (again based on continued performance). But at the Ivies, the coaches commit without any review from admissions. Sometimes, even well-intentioned coaches get it wrong at an Ivy because the admissions committee changes their emphasis or requirements from previous years. Clearly, at Harvard (at least as reported by others on this forum), that is leading to 1 or 2 "failed admission" commitments per year.
Be very interested to hear from any others with recent experiences with Princeton, Harvard, or other Ivies that suggest the admissions committee is reviewing players academics prior to the summer (I think, but can't definitively state, that there may even be a league rule against this).